••• Chapter 13^ Hypertension and Pregnancy^121
❍ What is the initial treatment of severe preeclampsia prior to 34 weeks?
Hospitalization to evaluate maternal and fetal status: Blood pressure monitoring, strict documentation of intake
and output, 24-hour urine collection and laboratory studies such as complete blood count (CBC), basic metabolic
panel, liver function tests and possibly lactate dehydrogenase (LDH), uric acid, albumin, and coagulation studies.
The fetal status is evaluated by NST, amniotic fluid index (AFI), fetal growth, and possible umbilical artery Doppler
velocimetry. Corticosteroids should be administered and magnesium should be given for seizure prophylaxis.
❍ How should preeclampsia with onset before 23 to 25 weeks be managed?
Pregnancy should be delivered with no role of expectant management.
❍ Who is a candidate for expectant management?
Asymptomatic women with laboratory abnormalities that resolve within 24 to 48 hours, severe preeclampsia due
to severe proteinuria alone, severe preeclampsia based solely on fetal growth restrictions, and severe preeclampsia
based solely on blood pressure criteria.
❍ What are contraindications to expectant management (in which the pregnancy is not even prolonged
enough to receive the second dose of steroids)?
Women with eclampsia, pulmonary edema, disseminated intravascular coagulation (DIC), renal insufficiency,
abruptio placentae, abnormal fetal testing, HELLP syndrome, or persistent symptoms of severe preeclampsia. For
women with severe preeclampsia before the limit of viability, expectant management has been associated with
frequent maternal morbidity with minimal or no benefits to the newborn.
❍ Who can be managed on an outpatient basis for preeclampsia?
Ambulatory management is possible for those women with mild gestational hypertension or preeclampsia remote
from term who are also compliant with their management plan.
❍ What is the medical management of preeclampsia during labor and delivery?
Magnesium sulfate is the treatment of choice for severe preeclampsia and is aimed at preventing seizures or
eclampsia and controlling hypertension. Antihypertensive treatment is recommended for diastolic blood pressure
of 105 to 110 mmHg or higher or systolic blood pressure over 160 mmHg.
❍ Why is the use of magnesium sulfate in mild disease controversial?
The risk of seizures in this group is considered low, and is balanced against the toxicity of magnesium. However, a
report from Parkland in 2006 demonstrated an increase in the incidence of eclampsia following their decision not
to treat mild gestational hypertension with magnesium.
❍ What is the mechanism of action of magnesium sulfate in seizure prophylaxis?
The exact mechanism of action is unclear but is thought to affect cardiovascular and neurological functions by
altering calcium metabolism. Magnesium sulfate may also act as a vasodilator, which relieves vasoconstriction,
protects the blood-brain barrier, decreases cerebral edema formation, and acts as a cerebral anticonvulsant.
❍ Name the two most common antihypertensive medications used for acute therapy.
Labetalol (20 mg IV followed by 40, 80, and 80 as needed with 10 minutes interval) or hydralazine (5–10 mg IV
every 15–20 minutes).